1. Technical Field
This invention is generally directed to flexible tubular joints for use in risers and pipelines and, more particularly, to a method and apparatus for sealing an end-to-end connection of a pair of tubular members while allowing limited pivotal movement therebetween.
2. Description of the Related Art
In the field of risers and pipelines used transmission of fluids, it is known to provide pivotal couplings between each of the pipe sections to allow for limited articulated movement therebetween and reduce undesirable stress. Accordingly, numerous flexible but sealed joints have been proposed for interconnecting the sections of the risers and pipelines, and these joints have been generally successful.
However, where the pipeline and/or riser is used to communicate invasive gases, such as petroleum gases and CO.sub.2, the gases have a tendency to attack or saturate any rubber components used in the pivotal joint. For example, where flexible rubber links are used to seal a pivotal connection, the invasive gases are known to migrate through the rubber surface and into the body of the rubber device. If the saturated rubber is then suddenly decompressed, the gas expands and forms large pockets or blisters. This phenomena is generally referred to as "blistering due to explosive decompression."
Once the outer rubber surfaces are damaged by this "blistering," the protective cover ultimately fails and exposes the interior of the bearing to the corrosive gases. Bearings typically used in these flexible joints are commonly constructed from laminations of steel and rubber. Accordingly, the rubber laminations of the bearing are similarly affected by the invasive gases and ultimately also fail. Further, the steel laminations are corroded and ultimately also fail.
The present invention is directed to overcoming or minimizing one or more of the problems discussed above.